Copper(II) Schiff base complex derived from salen ligand: structural investigation, Hirshfeld surface analysis, anticancer and anti-SARS-CoV-2.

This work deals with the synthesis and characterization of copper(II) complex [Cu(salen)(H2O)](1) of salen-type Schiff base ligand derived from the condensation of 5-bromo-2-hydroxy-3-methoxybenzaldehyde and ethylenediamine in EtOH. This complex was characterized by different spectroscopic and physicochemical methods. Single crystal X-ray crystallography study revealed that Cu(II) in complex (1) is five-coordinate and adopts a distorted square pyramidal geometry. A DFT calculation was employed to evaluate the optimized electronic structure, HOMO-LUMO, energy gap, and global parameters. A detailed structural and non-covalent interaction on the complex is investigated by single crystal structure analysis and computational approaches. The strength of the interaction and 3D topology of the crystal packing are visualized through an energy framework. Hirshfeld surface and 2D fingerprint plots have been explored in the crystal structure of the complex. The anticancer properties of copper(II) complex was studied against the selected cancerous cell lines of breast cancer, cervical cancer, colon cancer and hepatocellular carcinoma. Additionally, molecular docking and MD simulations was performed on the complex to predict the binding mode and interactions between the ligand and the main protease of the SARS-CoV-2 (PDB ID: 7CBT and 7D1M). The molecular docking calculations of the complex (1) with SARS-CoV-2 virus revealed the binding energy of -8.1 kcal/mol and -7.5 kcal/mol with an inhibition constant of 3.245 µM and 2.318 µM at inhibition binding site of receptor towards 7CBT and 7D1M main protease (Mpro), respectively. Besides this, molecular docking results (-7.6 kcal/mol, 3.196 µM) towards Escherichia coli PBP2 targets (PDB ID: 6G9S) was also studied. Communicated by Ramaswamy H. Sarma.

Structural and Computational Studies of Cobalt(II) and Copper(II) Complexes with Aromatic Heterocyclic Ligand

Two coordination complexes, a cobalt(II) complex tris(1,10-phenanthroline)-cobalt perchlorate hydrate, [Co(phen)3]·(ClO4)2·H2O(1), and a copper(II) complex tris(1,10-phenanthroline)-copper perchlorate 4-bromo-2-{[(naphthalene-1-yl)imino]methyl}phenol hydrate, [Cu(phen)3]·(ClO4)2·HL·[O] (2), [where, phen = 1,10-phenathroline as aromatic heterocyclic ligand, HL = 4-bromo-2-((Z)-(naphthalene-4-ylimino) methyl) phenol] have been synthesized and structurally characterized. Single crystal X-ray analysis of both complexes has revealed the presence of a distorted octahedral geometry around cobalt(II) and copper(II) ions. density functional theory (DFT)-based quantum chemical calculations were performed on the cationic complex [Co(phen)3]2+ and copper(II) complex [Cu(phen)3]2+ to get the structure property relationship. Hirshfeld surface and 2-D fingerprint plots have been explored in the crystal structure of both the metal complexes. To find potential SARS-CoV-2 drug candidates, both the complexes were subjected to molecular docking calculations with SARS-CoV-2 virus (PDB ID: 7BQY and 7C2Q). We have found stable docked structures where docked metal chelates could readily bound to the SARS-CoV-2 Mpro. The molecular docking calculations of the complex (1) into the 7C2Q-main protease of SARS-CoV-2 virus revealed the binding energy of −9.4 kcal/mol with a good inhibition constant of 1.834 µM, while complex (2) exhibited the binding energy of −9.0 kcal/mol, and the inhibition constant of 1.365 µM at the inhibition binding site of receptor protein. Overall, our in silico studies explored the potential role of cobalt(II) complex (1), and copper(II) complex (2) complex as the viable and alternative therapeutic solution for SARS-CoV-2.

Synthetic Aromatic Organic Compounds Bearing 4, 4-Dimethyl-3-Thiosemicarbazide Moiety: Theoretical and Experimental Approach

A theoretical and experimental approach for a series of synthetic aromatic organic compounds as salicylaldehyde thiosemicarbazones were prepared from 4,4-dimethyl-3-thiosemicarbazide and substituted salicylaldehydes. The newly synthesized compounds were fully characterized by FT-IR, UV-vis, 1H-NMR, 13C-NMR, CHNS, HRMS, and fluorescence spectroscopy. DFT calculations were performed on the compounds to get a structure-property relationship. Some global reactivity descriptors like chemical potential (μ), electronegativity (χ), hardness (η), and electrophilicity index (ω) were also evaluated using DFT method. Optical nonlinearity response of our novel compounds was also studied which may be significant for the hi-tech NLO applications. These compounds were also evaluated for their antibacterial activities against certain strains of Gram-positive and Gram-negative bacteria. They displayed moderate activity against using bacterial strains. Additionally, inspiring from recent developments to find a potential inhibitor for COVID-19 virus, molecular docking calculations were also performed on studied compounds to see if our novel compounds show affinity for main protease (Mpro) of SARS-CoV-2 (PDB ID: 6LU7). We have found stable docked structures where docked compounds could readily bound to the SARS-CoV-2, which would be lethal to main protease (Mpro). The molecular docking calculations of the present compounds into the protease of SARS-CoV-2 virus revealed the binding energy in the range of −7.86 to 9.92 kcal/mol with inhibition constant values in the range of 1.360–5.820 µM. These binding affinities are reasonably well as compared to recently docking results of anti-SARS-CoV-2 drugs like chloroquine (−6.293 kcal/mol), hydroxychloroquine (−5.573 kcal/mol) and remdesivir (−6.352 kcal/mol) when targeted to the active-site of SARS-CoV-2 main protease (Mpro). [ FROM AUTHOR] Copyright of Polycyclic Aromatic Compounds is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Structural and theoretical investigations, Hirshfeld surface analysis and anti-SARS CoV-2 of nickel (II) coordination complex.

A nickel(II) Schiff base complex, [Ni(L)(DMF)](1), was synthesized by treating NiCl2.6H2O with an ONS-donor Schiff base ligand(H2L) derived from the condensation 3,5-Dichlorosalicylaldehyde and 4,4-Dimethyl-3-thiosemicarbazide in DMF. The geometry around the center metal ion in [Ni(L)(DMF)](1) was square planar as revealed by the data collection from diffraction studies. DFT calculations were performed on the complex to get a structure-property relationship. Hirshfeld surface analysis was also carried out in the crystal structure of nickel (II) Schiff base complex. Additionally, inspiring from recent developments to find a potential inhibitor for SARS-CoV-2 virus, we have also performed molecular docking study of [Ni(L)(DMF)](1) to see if our novel complex show affinity for main protease (Mpro) of SARS-CoV-2 Mpro (PDB ID: 6LZE). Interestingly, the results are found quite encouraging where the binding affinity and inhibition constant was found to be -6.6 kcal/mol and 2.358 µM, respectively, for the best docked confirmation of complex [Ni(L)(DMF)](1) with Mpro protein. This binding affinity is reasonably well as compared to recently known antiviral drugs. For instance, the binding affinity of complex [Ni(L)(DMF)](1) is found to be better than that of recently docking results of anti-SARS-CoV-2 drugs like chloroquine (-6.293 kcal/mol), hydroxychloroquine (-5.573 kcal/mol) and remdesivir (-6.352 kcal/mol) when targeted to the active-site of SARS-CoV-2 Mpro. Besides this, molecular docking against G25K GTP-nucleotide binding protein (PDB ID: 1A4R) was also studied. We believe that current results can intrigue not only for the biomedical community but also for the materials chemists who are engaged to explore the application coordination complexes.Communicated by Ramaswamy H. Sarma.

New Ni(II) and Cu(II) Schiff base coordination complexes derived from 5-Bromo-salicylaldehyde and 3-picoyl amine/ethylenediamine: Synthesis, structure, Hirshfeld surface and molecular docking study with SARS-CoV-2 7EFP-main protease

Two co-ordination compounds, one nickel(II) complex [Ni(L1)(Phen)2]ClO4 (1) and one copper(II) complex [Cu(L2)] (2), were synthesized using Schiff base ligands derived from the condensation reaction of 5-Bromo-salicylaldehyde with 3-picoyl amine (L1H)(L1H = (E)-4-Bromo-2-(((pyridin-3-ylmethylene)amino) methyl) phenol) and ethylenediamine (L2H2), respectively(L2H2 = 2,2′-((1E,1′E)-(ethane-1,2-diylbis(azaneylylidene))bis(methanelylidene))bis (4-bromophenol)). The newly synthesized complexes were fully characterized, including X-ray crystallography. The crystal structure of both the complexes was determined using Single Crystal structure analysis. The electrochemical properties of (1) were studied using cyclic voltammetry. DFT calculations were done for the newly synthesized co-ordination complexes to have a relevant and reasonably accurate calculation of their molecular and electronic behavior. The Hirshfeld surface (HS) analysis was also performed using the crystallographic data for investigating the nature and quantitative contribution of all possible non-covalent intermolecular interactions within the crystal lattice. To explore potential SARS-CoV-2 drug candidates, both the co-ordination compounds were subjected to molecular docking calculations with the SARS-CoV-2 virus (PDB ID: 7EFP). The molecular docking calculations of Ni(II) complex (1) into the 7EFP-main protease of SARS-CoV-2 virus revealed the binding energy of −11.5 kcal/mol, while Cu(II) complex (2) exhibited the binding energy of −8.5 kcal/mol at the inhibition binding site of the receptor protein.

Design, synthesis and characterization of novel Ni(II) and Cu(II) complexes as antivirus drug candidates against SARS-CoV-2 and HIV virus.

This paper describes the structure-based design, synthesis and anti-virus effect of two new coordination complexes, a Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) of (E)-N-phenyl-2-(thiophen-2-ylmethylene) hydrazine-1-carbothioamide(HL). The synthesized ligand was coordinated to metal ions through the bidentate-N, S donor atoms. The newly synthesized complexes were characterized by various spectroscopic and physiochemical methods, powdered XRD analysis and also X-ray crystallography study. Ni(II) complex [Ni(L)2](1) crystallize in orthorhombic crystal system with the space group Pbca with four molecules in the unit cell (a = 9.857(3) Å, b = 7.749(2) Å, c = 32.292(10) Å, α = 90°, ß = 90°, γ = 90°, Z= 4) and reveals a distorted square planar geometry. A Hirshfeld surface and 2D fingerprint plot has been explored in the crystal structure of Ni(II) complex [Ni(L)2] (1). Energy framework computational analysia has also been explored. DFT based calculations have been performed on the Schiff base and its metal complexes to study the structure-property relationship. Furthermore, the molecular docking studies of the ligand and its metal complexes with SARS-CoV-2 virus (PDB ID: 7BZ5) and HIV-1 virus (PDB ID: 6MQA) are also investigated. The molecular docking calculations of the Ni(II) complex [Ni(L)2] (1) and a Cu(II) complex [Cu(L)2] (2) with SARS-CoV-2 virus revealed that the binding affinities at inhibition binding site of receptor protein are 9.7 kcal/mol and -9.3 kcal/mol, respectively. The molecular docking results showed that the binding affinities of Ni(II) complex (1) and Cu(II) complex (2) against SARS-CoV-2 virus were found comparatively higher than the HIV-1 virus (-8.5 kcal/mol and -8.2 kcal/mol, respectively). As potential drug candidates, Swiss-ADME predictions analyses are also studied and the results are compared with Chloroquine (CQ) and Hydroxychloroquine (HCQ) as anti-SARS-CoV-2 drugs.

Synthesis, crystal structure, computational study and anti-virus effect of mixed ligand copper (II) complex with ONS donor Schiff base and 1, 10-phenanthroline.

This work deals with the synthesis, crystal structure, computational study and antiviral potential of mixed ligand copper(II) complex [Cu(L)(phen)](1), (where, H2L = (Z)-N'-((E)-2-hydroxy-3,5-diiodobenzylidene)-N,N-dimethylcarbamohydrazonothioic acid, phen = 1,10-phenanthroline). The Schiff base ligand (H2L) is coordinated with Cu(II) ion in O, N, S-tridentate mode. The copper complex (1) crystallized in the monoclinic system of the space group P21/c with eight molecules in the unit cell and reveals a square pyramidal geometry. Furthermore, we also perform quantum chemical calculations to get insights into the structure-property relationship and functional properties of ligand (H2L) and its copper (II) complex [Cu(L)(phen)](1). Complex [Cu(L)(phen)](1) was also virtually designed in-silico evaluation by Swiss-ADME. Additionally, inspiring by recent developments to find a potential inhibitor for the COVID-19 virus, we have also performed molecular docking study of ligand and its copper complex (1) to see if our compounds shows an affinity for the main protease (Mpro) of COVID-19 spike protein (PDB ID: 7C8U). Interestingly, the results are found quite encouraging where the binding affinity and inhibition constant were found to be -7.14 kcal/mol and 5.82 µM for ligand (H2L) and -6.18 kcal/mol and 0.76 µM for complex [Cu(L)(phen)](1) with Mpro protein. This binding affinity is reasonably well as compared to recently known antiviral drugs. For instance, the binding affinity of ligand and complex was found to be better than docking results of chloroquine (-6.293 kcal/mol), hydroxychloroquine (-5.573 kcal/mol) and remdesivir (-6.352 kcal/mol) with Mpro protein. The present study may offer the technological solutions and potential inhibition to the COVID-19 virus in the ongoing and future challenges of the global community. In the framework of synthesis and characterization of mixed ligand copper (II) complex; the major conclusions can be drawn as follow.